40 years ago today, Led Zeppelin released IV, the album that includes “Stairway To Heaven.” This seems about right. Actually, it’s always seemed about right. For the twenty-some years that “Stairway To Heaven” has existed in my consciousness, “Stairway To Heaven” has seemed to be about 40 years old. I can’t imagine a reality when people were listening to, arguably, the most grandly ridiculous song in rock history when it actually came out.

In its sands-of-time mysticism and its inexorable whisper-to-wail build, “Stairway To Heaven” doesn’t seem like the sort of song that human beings sit down to write. All those old something-out-of-nothing story-pegs — the lyrics scrawled on crumpled notebook paper, the first muddy rehearsal run-through, the band hearing the track on the radio for the first time — seem like they couldn’t possibly apply to this eight-minute monolith. Instead, the song has exactly the sort of power that exists for people to joke about. The lyrics are ridiculous, sure, and the Lord Of The Rings flutes and balls-out soloing are the sorts of things that seem adolescent even when you’re actually an adolescent. But all the things that make “Stairway” absurd are the same things that make it great. Because it is great.

Consider, if you can bring yourself to do it, this endless deleted scene from Almost Famous, a scene that reportedly only got clipped because Cameron Crowe couldn’t get the rights to the song but which would’ve ground the movie to a halt if it’d made it in. The scene, in which Patrick Fugit attempts to convince Frances MacDormand and a roomful of grown-ups of the song’s worth, is both hilarious and deeply, deeply wince-worthy. On most of those faces, we eventually see an enthusiasm for the song that strikes me as perfectly genuine — natural, even. But the painful earnestness of that venture, and the entire enterprise of rocking out in front of your mom, also peg it as the sort of thing that brings on a full-body cringe when you remember it later.

“Stairway” may be a prototypical power-ballad, but it’s hard to judge its place within rock history. Did it actually influence anything? Did “Every Rose Has Its Thorn” and “Silent Lucidity” reach for “Stairway”-hood? Could any song possibly aspire to “Stairway”-hood? “Freebird,” even? I honestly have no idea.

But let’s all listen to the song together anyway. Happy birthday, “Stairway.”